__________________
How to ride your XR650L to South America: http://advrider.com/forums/showthrea...2#post19932112
If you're in my area on a ride and need a place to crash, a hot meal, or some beer let me know. 913 260 7873
On a one man mission to stop people from buying boring bikes (cough cough klr)

does HDPE/Seaboard/Starboard relax enough when heated in an oven to form compound curves if a mold is used? if used as a skidplate, what is the recommended minimum separation distance to the exhaust?

My experience was with Seaboard:
Yes, but getting to the exact temp. is tricky and at that temp. the mold may distort/indent the plastic. I accidently over heated a sheet and it squeezed out of the mold at the edges. You need to get all the bends in one shot in the mold. If you reheat the sheet for the second bend it will go back to flat. I've tried heating the sheet in the mold and at 240/270 the wood was fine.
Run some trials before committing the whole project sized sheet.

From the photos of my rack you can see the plastic is very close to the muffler and there were no issues with there.

What you might do is to make two molds.
Make the first break and leave the sheet clamped in the mold. Re - heat both together then place the first mold with sheet in a second mold to make the second break.

24x24" sheet of 1/4" startboard on the way. Plan is to use 8mm stainless buttonhead Allen screws to secure.

I would use stainless slotted countersunk screws and set them just below flush. This gives you some room before a gouge in the soft plastic gets to metal. Remember the plastic will not support the screw. Hit the screw on a rock and it will bend sideways. HDPE is not nearly as abrasion resistant as UHMW-PE, which would have been my choice (and you can get cheap cutting boards at the thrift store to cut up)

The allen fastener packs up with crap and in stainless they are strip monsters. Stainless is soft stuff. The slotted head is easy to clean and get a tool on, especially in the field.

I would use stainless slotted countersunk screws and set them just below flush. This gives you some room before a gouge in the soft plastic gets to metal. Remember the plastic will not support the screw. Hit the screw on a rock and it will bend sideways. HDPE is not nearly as abrasion resistant as UHMW-PE, which would have been my choice (and you can get cheap cutting boards at the thrift store to cut up)

The allen fastener packs up with crap and in stainless they are strip monsters. Stainless is soft stuff. The slotted head is easy to clean and get a tool on, especially in the field.

For impact, Kydex is tops.

The polyethelenes cold flow, don't store on edge.

Well, I did this on a whim sort of. The hardware I had on hand. I will likely recess the front two M6 bolts like you said, and the rears will never see contact, or I'm in big trouble ripping off the rear shock linkage. I went with the Starboard from McMaster as it was UV stable, and mold/mildew resistant.

Well, I did this on a whim sort of. The hardware I had on hand. I will likely recess the front two M6 bolts like you said, and the rears will never see contact, or I'm in big trouble ripping off the rear shock linkage. I went with the Starboard from McMaster as it was UV stable, and mold/mildew resistant.

I did one kinda on a whim too---out of brazed stainless. I'll do plan B in the spring and will likely go with plastic. Mine's a road bike with an extended sump so I'll just build it as a one hit wonder. It'll save me once then I make another or bolt it back on.

Do you ever have to take that plate off in the field for anything?

How to you get UV on something facing down? Mold??? Got vinyl on the seat? If you have some scraps you might try wiring one to a brick and drag it behind on a rope sometime and see how it does.

I'm a huge fan of those buttonheads---got 'em everywhere. Just like the look. But one little blob of road tar or a smashed bug in one and life sucks.

I can't imagine why I'd ever have to take it off to access anything besides cleaning. Oil drain is from the side which I'm not sure how I'll address yet, maybe a small hole ~3/4 hole saw? and if I need to remove the rear shock linkage in the woods I'm in real deep anyways... I leaned towards UV stable with mildew resistance knowing it'll get wet all the time. Just didn't want it to deteriorate in the sun like some plastics can. I actually found two countersunk head metric phillips (larger P3 size) M6 aftermarket stainless screws from Audi brake rotors on my bench that the new rotors didn't have the provisions for that I'll be countersinking and installing soon. Strike of luck if anything. I doubt I'll really "road test" a chunk. My intentions are for log crossing vs desert rock gardens here in the northeast.

I can't imagine why I'd ever have to take it off to access anything besides cleaning. Oil drain is from the side which I'm not sure how I'll address yet, maybe a small hole ~3/4 hole saw? and if I need to remove the rear shock linkage in the woods I'm in real deep anyways... I leaned towards UV stable with mildew resistance knowing it'll get wet all the time. Just didn't want it to deteriorate in the sun like some plastics can. I actually found two countersunk head metric phillips (larger P3 size) M6 aftermarket stainless screws from Audi brake rotors on my bench that the new rotors didn't have the provisions for that I'll be countersinking and installing soon. Strike of luck if anything. I doubt I'll really "road test" a chunk. My intentions are for log crossing vs desert rock gardens here in the northeast.

I would use a UniBit for a 3/4" hole. (step bit) Very clean. On plastic you can just use a cheapo Harbor Fright one and it will work great. Not good for hard plastics (like plexi.) But the polyethylenes and abs; perfect.

Screws sound sweet. I'm up against curbs (oops!) and the occasional rock hidden in the tall grass in some field when looking for a cat-out tent site. I'm just tired of chewing the fins off oil pans.

I made UHMWPE skid plates for our trials bike in the early "70's because the aluminum ones would hang up on rocks. Used 1/4 " .....it's indestructible and slick which is what we wanted. I use a propane torch with a big bushy flame and keep it moving. It will melt/burn if you're not careful. A heat gun will work, but it's slow. I use jacks, straps and tie downs (and anything else I can think of) to hold it in place till it cools. Made one not too long ago for a KLR.